Disclosed are a people counting device and a method for counting the number of people capable of executing built-in artificial intelligence (AI) algorithms and/or machine learning algorithms to count the number of people and communicating with user terminals and servers in a 5G communication environment. The method according to an embodiment of the present disclosure can include collecting, by a first collector, probe request packets for a predetermined time from a user terminal transmitting the probe request packets to confirm the existence of an access point, measuring, by a measurer, the density of the probe request packets and generating density data, and estimating, by a estimator, the number of people using a people counting learning model pre-trained to count people according to the density of the probe request packets based on the density data generated by collecting the probe request packets from the user terminal.